/**
 * 返回 void 类型
 * */

type voidFunc = () => void

const f1: voidFunc = () => {
  return false
}

const f2: voidFunc = () => true

const f3: voidFunc = function () {
  return false
}

const v1: void = f1()
const v2 = f2()
const v3 = f3()

console.log(v1, v2, v3)